Evaluation of quantity and quality of biodiesel produced from jatropha curcas in different parts of Kenya
ABSTRACT Biodiesel as an alternative fuel for diesel engines is becoming increasingly important due to diminishing petroleum reserves and the environmental consequences of exhaust gases from petroleum-fuelled engines. The availability and sustainability of sufficient supplies of less expensive feedstock will be a crucial determinant delivering a competitive biodiesel to the commercial filling stations. Fortunately, inedible vegetable oils, mostly produced by seed-bearing trees and shrubs can provide this much desired alternative. With no competing food uses, this characteristic makes Jatropha curcas a preferred alternative. Jatropha curcas is a non-edible oil crop predominately used to produce bio-diesel. The seeds contain 27-40% oil (average: 34.4%) that can be processed to produce a high-quality biodiesel fuel, usable in a standard diesel engine. There is need therefore to determine the jatropha with the highest quality and quantity to be developed. The objective of this study was to evaluate the characteristics of biodiesel produced from Jatropha curcas oil in Kenya using trans-esterification process. Straight jatropha oil was extracted and its physical and chemical properties analysed. The oil was transeterified to produce its methyl ester which is jatropha biodiesel. The physical and chemical properties were analysed and compared to the standard requirements. From the results obtained, straight Jatropha oil was unsuitable for direct usage as fossil fuel substitute but had to undergo trans-esterification to produce biodiesel. For instance the density of Jatropha seed oil was between 1.0802 - 1.0864 g/cm ' at 200e whereas that of biodiesel was in the range of 0.8786-0.8808 g/crrr', the standard for biodiesel states that the fuel should have a density between 0.860 and 0.900 g/crrr'. Acid value of Jatropha oil was between 1.35 - 4.19 mgKOHlg and that of the biodiesel was between 0.31 - 0.86 mgKOHlg, kinematic viscosity of biodiesel was between 4.3 to 4.8mm2/s at 40°C. The parameters of the biodiesel produced were in agreement with ASTM standards of biodiesel and is a suitable substitute for fossil fuel.